Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual taxa bruta de mortalidade (por 1000) tem Mortes de 768 e uma taxa de natalidade bruta (por 1000) menor que 29,7?
 ###Tabelas: CREATE TABLE railway_stations_currently_in_use (railway_stations_currently_in_use_id AUTO_INCREMENT PRIMARY KEY, Station (and code) VARCHAR, Managed by VARCHAR, Lines served VARCHAR, Station users 2007/8 INT, Station users 2008/9 VARCHAR, Year opened VARCHAR, Platforms VARCHAR, Borough VARCHAR) CREATE TABLE heavyweight___105_kg (heavyweight___105_kg_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Bodyweight INT, Snatch VARCHAR, Clean & Jerk VARCHAR, Total (kg) VARCHAR) CREATE TABLE registered_births_and_deaths (registered_births_and_deaths_id AUTO_INCREMENT PRIMARY KEY, Average population (x 1000) INT, Live births VARCHAR, Deaths VARCHAR, Natural change VARCHAR, Crude birth rate (per 1000) INT, Crude death rate (per 1000) INT, Natural change (per 1000) INT) CREATE TABLE senior_pga_tour_wins_11 (senior_pga_tour_wins_11_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Tournament VARCHAR, Winning score VARCHAR, Margin of victory VARCHAR, Runner(s)-up VARCHAR) CREATE TABLE biosynthesis (biosynthesis_id AUTO_INCREMENT PRIMARY KEY, Enzyme VARCHAR, Location VARCHAR, Substrate VARCHAR, Product VARCHAR, Chromosome VARCHAR, EC VARCHAR, OMIM INT, Porphyria VARCHAR)  
SELECT MIN Crude death rate (per 1000) FROM registered_births_and_deaths WHERE Deaths = 768 AND Crude birth rate (per 1000) < 29.7